SWR Meter Hi i purchased a radio shack strength/ swr meter and it didn`t have any instructions in it for tuning your cb to your antenna, the model is MICRONTA cat # 21-525B by the tandy corporation,can you obtain a instruction sheet on how to use this ?? Thanks Jack

Thank You The information !!!!It was excellent and the response to the question was fast!!!!!!!!!! Thanaks again Sincerely JackThank You The information !!!!It was excellent and the response to the question was fast!!!!!!!!!! Thanaks again Sincerely Jack

Dont if you got sorted out but sw goes inline with aerial.
cb,patch lead to sw aerial to sw.set sw with variable to to check standing wave calibration.also if you want to use a linear amplifier or a frequency counter you put them inline same way.

No problem,
Follow the link
http://support.radioshack.com/productinfo/DocumentResults.asp?sku_id=21-525&Name=CB%20Accessories&Reuse=N
It's off to the right under other documents.
Good Luck
and hope this helps
L8R

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Sounds like a antenna issue. Make sure coax is in good order.and antenna is connected properly. You might have to get a "swr" meter to put in line between radio and antenna to make sure antenna is "tuned" to were the radio is operating. Radio shack sells a ok low budget swr/power meter.

Here is a basic instruction on how to adjust the SWR. When you adjust the SWR, you are not changing anything on the radio. You are actually tuning the antenna for best SWR. The lower the better. SWR stands for "Standing Wave Ratio" Or in layman's terms, SWR is energy that is reflected back into the radio. The higher your SWR reading, the more RF energy that is not leaving the antenna, and getting reflected back into the radio. This can cause damage to the transmit section of the radio. The length of the antenna is what will change this. The length of the antenna must match the length of the radio wave. The following instruction will explain how to take an SWR reading, and how to use that reading to ascertain weather the antenna is too long or too short.

Here is a quick explanation of the meter. There are 3 settings for the meter. SWR, MOD, and PWR. When you are not keying the radio the meter will show you your receive signal. How strong some ones signal is. When you have the switch on MOD and key, when you talk it shows you modulation. How much audio you are putting through the radio. When its on power, and you key the radio, it shows you your dead key wattage.

Tuning your antenna:

It is important to tune your CB radio antenna to the proper length. The length must exactly match the wavelength of the frequency you transmit on. Or be really really close.

All Cb antenna's have a way to adjust the length of the antenna. If it's a mag mount, the metal whip can be slid in and out of a metal collar. Usually a set screw. If its a fiberglass whip, the way to tune it is on top. It either has a small metal rod with a set screw to adjust the length, or it threads in and out to adjust length.

Either type you have it will need to be adjusted for proper length. Here is how to tune the antenna to lowest SWR.

Some radios have a built in SWR meter. Some do not. If yours doesn't have an SWR meter, then you have to use an external SWR meter. Radio shack carries one, and you can find them cheap on ebay.

If you have a built in SWR meter or external, the procedure is the same:

1. Turn the radio to CH 20.(This is the center of the band.) 2. Switch the meter switch to SWR 3. Key the radio. (Important. Do not talk while keying the radio.)

Where the meter falls after that point is you SWR reading. If its above 3, that is real bad. 2 is not gonna kill your radio but its not the greatest. 1.5 and under is a good place to be, but the lower the better.

If your SWR is high, Here is how to find out if your antenna is too long or too short.

1. Turn to CH 1 2. Repeat SWR procedure. You must calibrate every time you do it. 3. Remember the SWR reading. 4. Turn to CH 40. 5. Again repeat SWR procedure. 6. Compare the reading between CH 1 and CH 40.

Now if the SWR is higher on channel 1 then channel 40 your antenna is too short. You must make it longer.

If the SWR is longer on channel 40 then on channel 1, then the antenna is too long, you need to make it shorter.

Make height adjustments about an eight inch at a time, and take reading each time.

once the SWR is significantly lower and the reading on channel 1 and 40 are about the same, you a about matched. At this point turn the radio to the center of the band, channel 20 and take an SWR reading.

You should now have a low SWR reading, 1.5 or under. If you are 1.5 or under, you are good to go.

If you cannot get the SWR to an appropriate level, there may be an antenna problem.

If this radio has been peaked and tuned already, and it is not in need of a full alignment, then it's most likely the antenna.

Your antenna is everything. You need a good antenna, and it needs to be tuned to the lowest SWR.

It is important to tune your CB radio antenna to the proper length. The length must exactly match the wavelength of the frequency you transmit on. Or be really really close.

All Cb antenna's have a way to adjust the length of the antenna. If it's a mag mount, the metal whip can be slid in and out of a metal collar. Usually a set screw. If its a fiberglass whip, the way to tune it is on top. It either has a small metal rod with a set screw to adjust the length, or it threads in and out to adjust length.

Either type you have it will need to be adjusted for proper length. Here is how to tune the antenna to lowest SWR.

Some radios have a built in SWR meter. Some do not. If yours doesn't have an SWR meter, then you have to use an external SWR meter. Radio shack carries one, and you can find them cheap on ebay.

If you have a built in SWR meter or external, the procedure is the same:

1. Turn the radio to CH 20.(This is the center of the band.) 2. Switch the meter switch to CAL. (CAL stand for calibrate. 3. Key the radio. (Important. Do not talk while keying the radio.) 4. turn the CAL knob up until the meter hits the CAL mark. 5. Now while still keying the radio flip the meter switch to SWR.

Where the meter falls after that point is you SWR reading. If its above 3, that is real bad. 2 is not gonna kill your radio but its not the greatest. 1.5 and under is a good place to be, but the lower the better.

If your SWR is high, Here is how to find out if your antenna is too long or too short.

1. Turn to CH 1 2. Repeat SWR procedure. You must calibrate every time you do it. 3. Remember the SWR reading. 4. Turn to CH 40. 5. Again repeat SWR procedure. 6. Compare the reading between CH 1 and CH 40.

Now if the SWR is higher on channel 1 then channel 40 your antenna is too short. You must make it longer.

If the SWR is longer on channel 40 then on channel 1, then the antenna is too long, you need to make it shorter.

Make height adjustments about an eight inch at a time, and take reading each time.

once the SWR is significantly lower and the reading on channel 1 and 40 are about the same, you a about matched. At this point turn the radio to the center of the band, channel 20 and take an SWR reading.

You should now have a low SWR reading, 1.5 or under. If you are 1.5 or under, you are good to go.

If you cannot get the SWR to an appropriate level, there may be an antenna problem.

You insert an SWR meter in the antenna line, usually one end goes into the Antenna OUT socket, and the Antenna plugs into the SWR meter, you then tune you antenna coupler, inductor, & final PA, in the final stage, until you achieve a 1:1 SWR reading, this is however quite hard to achieve, so simply tune for the closest 1:1 SWR that you can achieve.

After installing the antenna, follow these steps to adjust thestanding wave ratio(SWR).1. Turn on the CB.2. Set S/RF/SWR/CAL to CAL.3. Key the Mic and rotate SWR CAL so the meter pointsto CAL.4. Unkey Mic.5. Set S/RF/SWR/CAL to SWR.6. Key Mic again and note the actual measurement onthe SWR scale. Refer to the following table to interpretthe reading.

The ideal standing wave ratio (SWR) is 1:1, or a meterreading of 1 on the SWR meter's top scale. A SWR ratioof 1.5:1 to 2:1 is excellent for most mobile CB antennaapplications.

Check the SWR on Channel 1 and Channel 40If the SWR is higher on 1, make the antenna longerIf the SWR is higher on 40, make the antenna shorterMost antenna's are adjustable. Make small adjustments at a time.

The calibrate knob only calibrates the radios SWR meter, the owners manual will show you the procedure for that. If your ANT light is coming on, it is telling you that your SWR is to high, and may cause damage to the radio from reflected power. You should purchase an in line meter as the radios internal meter may be somewhat unreliable. You need to tune the antenna to the lowest SWR possible. Typically anything under 2.0:1 is acceptable. Radio Shack sells a meter for about $50, and is pretty accurate. Antenna mounting can also cause high reflection if it is to close to other objects. Google "CB antenna tuning" or read the instruction manual for you antenna, and you should be able to figure out how to properly tune the antenna.

If by calibration, you are referring to the check if your antenna is tuned, below information may be of help.S/RF/SWR/CAL SWITCH. When in the S/RF position, the meter swingsproportionally to the strength of the received signal. When transmitting,the meter indicates relative RF output power.When in the "CAL" position, the SWR meter can be calibrated by adjustingthe "SWR CAL" control to the "CAL" mark on the meter face.When in the "SWR" position, the standing wave ratio is measured.

SWR METER. Measures standing wave ratio of the antenna system.Used to properly adjust the length of the antenna and to monitor thequality of the coaxial cable and all RF electrical connections. If there is anydegradation whatsoever in any of the foregoing, due to humidity, saltspray, vibration or corrosion, the SWR meter reading will rise, therebyindicating that a problem exists.To calibrate, switch to the "CAL" position, transmit by pressing the mikeswitch, and adjust the SWR control to the "CAL" mark on the meter; thenswitch to "SWR" position for the SWR measurement.

If however you are referring to the internal calibration or tuning of the transmit and receive sections, you would need several instruments/equipment such as RF generator (0-30Mhz with 1Khx modulation), Spectrum Analyzer, Modulation Scope, Dummy Loaded Wattmeter, Frequency Meter and some others. These of course are not readily available to the average user.

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.